PHP can be used in HTML /CSS templates as long as the PHP is fairly limited. Obviously CMS solutions, etc. don’t belong in the HTML /CSS category. However, lots of buyers assume that because the files end with .php instead of .html that they won’t be able to use them. This is not the case.

In order for a server to process any PHP within a document, the document needs to end with .php. So, maybe the majority of the template is all HTML /CSS only but the navigation uses some PHP . You could easily replace the PHP with HTML only and rename all the files to .html instead of .php.

If you have any questions about the PHP you can usually refer to the help documentation or contact the author. You might even request that the other include an HTML only version of the template.